With the successful launch of the SpaDeX Mission, India is on track to become the fourth country, after the US, Russia, and China, to master space docking. This capability is crucial for the Indian space sector, serving as a foundation for future human spaceflights, the Chandrayaan-4 mission, and the development of the Bharatiya Antariksh Station (BAS).
ISRO launched the SpaDeX mission on December 30, 2024. The mission aims to demonstrate in-space docking using two 220-kg satellites—Chaser and Target—in a low-Earth circular orbit. The docking attempt is scheduled for January 7, as confirmed by ISRO Chairman S. Somanath.
But what exactly does docking mean?
You might have heard of the International Space Station (ISS), which serves as a home for humans in space. The US has sent multiple spacecraft with astronauts to the ISS, where they have carried out months-long missions in microgravity, with their spacecraft remaining “docked” at the station during their stay.
Docking refers to the process of two space objects coming together for a specific purpose.
“Docking” occurs when a spacecraft autonomously maneuvers to attach itself to a space station. According to NASA, docking is defined as “mating operations where an active vehicle flies into the mating interface under its own power.”
ISRO, on the other hand, explains that in-space docking technology is essential when multiple rocket launches are carried out to achieve shared mission objectives.
ISRO Chairman S. Somanath further clarified the concept in an interview, stating, “When there are multiple objects in space that need to be brought together for a specific purpose, a mechanism called docking is required.”
He explained that docking can be accomplished through various methods: soft mechanisms, hard mechanisms, or pressurized compartments for human transfer (which are used for moving astronauts between spacecraft).
“For instance, on the International Space Station, when a crew module connects to the station, the pressure is equalized, and astronauts are transferred,” Somanath explained.
The ISRO chief further explained that initially, a mechanism arrives and connects the objects, followed by the establishment of a sealed connection. “For example, if you want to build a space station, not everything is launched at once. Modules are sent one after the other and connected to each other to form a large, complex space station,” he said.
One of the objectives of ISRO’s SpaDeX mission is to demonstrate this docking process on January 7. The mission will involve docking two satellites in space: Chaser and Target.
What to Expect from the SpaDeX Mission
S. Somanath stated that the goal of the SpaDeX mission is to replicate the technology required for the docking process. He outlined the key aspects ISRO will be focusing on during the mission, which are as follows:
- Mechanism – How to connect two objects and secure them to form an integrated body.
- Control – How to manage the objects once they are integrated.
- Sensors – How to use a set of sensors to enable autonomous docking.
- Failure Handling – How to address failures if the docking process does not go as planned.
- Separation – How to safely disconnect the two spacecraft when necessary.
Why is a docking system important?
A docking system is crucial for India’s future missions. S. Somanath explained that SpaDeX is significant because constructing complex systems in space requires the ability to connect components effectively.
“So, how do we connect objects in space? The process can’t be the same as on the ground because these objects are moving at incredibly high speeds. Maneuvering at such speeds requires precision, a reliable control system, advanced sensors, and well-designed algorithms and software. We are testing all of these elements in space,” Somanath told India Today TV.